The present invention relates to a device for detecting a child seat attached to a vehicle seat.
Studies by (NHTSA) the National Highway Traffic Safety Administration in the United States, for example, have shown that deployment of an airbag when a child is restrained in a child seat attached to an automotive seat can cause serious injuries. Deployment of one or more airbags belonging to a vehicle seat with a child seat attached to it should therefore be suppressed in any case. Thus, a controller provided in the vehicle to control deployment of the airbags must receive a signal to indicate when a child seat is on a passenger seat so that the airbags assigned to this seat will not be deployed in the event of an accident. There are conventional devices that detect a child seat on a vehicle seat and signal this condition to the controller.
For example, German Patent No. 44 09 971 ; German Utility Model No. 296 19 668 U1 and U.S. Pat. No. 5,605,348 describe child seat detection devices that operate according to the transponder principle, where an identification carrier, which in the simplest case is an electromagnetic tuned circuit, is provided on the child seat, and a transmission element emitting an electromagnetic alternating field is provided in the vehicle seat. A receiver element in the vehicle seat records the change in field caused by the interaction between the identification carrier on the child seat and the electromagnetic field emitted by the transmitting element. However, such a child seat detection based on the transponder principle is extremely complicated and expensive.
German Patent Application No. 44 26 677 describes a device for attaching a child seat to a vehicle seat. This device has a belt lock housing that is attached to the vehicle so that a plug element on the child seat can be locked into it. The belt lock housing contains a switch mechanism that has a movable part, which is inserted on engagement of the plug element in the belt lock housing, thereby closing a contact that sends a signal to an airbag controller indicating that deployment of the airbag must be suppressed because of the child seat.
An object of the present invention is to provide a device for detection of a child seat attached to a vehicle seat that can be implemented at the lowest possible expense and yet detects with a very high reliability a child seat attached to a vehicle seat.
The object described above is achieved due to the fact that fastening means, which are installed on a vehicle seat and can be engaged with a plug element on the child seat, is provided with a switch mechanism. The switch mechanism has a stationary part attached to the fastening means and has a movable part, which is moved by the plug element into the stationary part on mutual engagement of the plug element with the fastening means, thereby activating a switch which signals that the passenger seat is occupied by a child seat.
The switch, for example, is a reed switch. In addition, there is a magnet that alters the position of the reed switch on displacement of the movable part into the stationary part.
Such a switch mechanism can be installed very easily and detects reliably whether a child seat has been attached to a vehicle seat. In addition, this switch mechanism is designed to be very space saving.
The switch is arranged, for example, in the stationary part of the switch mechanism, and the magnet is arranged, for example, in the movable part. The magnet is directly above the reed switch and closes/opens it when the movable part is in its starting position where it has not be affected by the plug element. The magnet is located a distance away from the switch and opens/closes it when the movable part has been displaced by the plug element.
The movable part may be, for example, a slide that is pushed by the plug element into the stationary part on mutual engagement of the plug element with the fastening means. A compression spring used in the stationary part keeps the slide in its starting position when the plug element has not been engaged.
The movable part may also be a lever that is pivotably mounted in the stationary part and flipped by the plug element into the stationary part on mutual engagement of the plug element with the fastening means. A tension spring inserted into the stationary part holds the lever in its starting position when the plug element has not been engaged.